1. Field of the Invention
This invention relates to a high magnification change rate zoom lens including a wide angle of view in which the maximum angle of view exceeds 70.degree. and having a wide focus range in which the zoom ratio is four times or more.
2. Description of the Prior Art
Of zoom lenses which include a wide angle in their magnification change range, various zoom lenses in which a first lens group has a positive refractive power and which has a zoom ratio of three times or more are known in recent years, and one of such zoom lenses is taught disclosed, for example, in Japanese Laid-open patent application No. 78114/1983 (U.S. Application Ser. No. 435,710). However, in any of these zoom lenses, the maximum angle of view included in the magnification change range is of the order of 62.degree., and it has been difficult to realize a high magnification change rate zoom lens system including a greater angle of view and having a zoom ratio of four times or more and a good optical performance over the entire magnification change range. Also, as a zoom lens including a wide angle in its magnification change range, one in which a first lens group has a negative refractive power and the maximum angle of view exceeds 70.degree. is known, but in such zoom lens, the first lens group has a negative refractive power and therefore, a second lens group having a considerably strong positive refractive power must be disposed as the subsequent lens group, and it has been difficult to maintain a good optical performance over the entire magnification change range when an attempt is made to realize a high magnification change rate zoom lens in which the zoom ratio is great.